Lower leg brace



April 23, 1963 s. DESAI ETAL 3,086,521

LOWER LEG BRACE Filed Feb. 6, 1961 2 Sheets-Sheet 1 INVENTORS 47SHRIKANT DESAI I W LLIAM H. HENDERSON /I f 48 BY CH R DCLIFF s 16 '56. 5KHZ/1y Ap 1963 s. DESAI E'I 'AL 3,086,521

LOWER LEG BRACE Filed Feb. 6, 1961 2 Sheets-Sheet 2 INVENTORS, SHRIKANTDEsAI WILLIAM HENDERSON H BY CHARLES w. (LII-Z5 AID.

United States Patent 3,086,521 LOWER LEG BRACE Shrikant Desai, Berkeley,William H. Henderson, Pacifica, and Charles W. Radcliffe, Lafayette,Calif., assignors to 'ghe Regents of the University of California,Berkeley,

Filed Feb. 6, 1961, Ser. No. 87,417 '7 Claims. (Cl. 12880) Thisinvention relates to bracing devices for human limbs and moreparticularly it relates to an improved leg brace of the below-knee orshort-leg type.

The major objective of the present invent-ion is to provide a greatlyimproved leg brace that not only affords adequate support for disabledor paralyzed human limbs, but which also provides for the normalarticulation of the foot about its natural anatomical axes and whichovercomes many serious deficiencies of prior art braces.

The leg-bracing problem, viewed from the standpoint of the necessary ordesirable performance of the bracing device, may be generally stated asbeing that of: first, providing adequate support or stability for thedisabled or paralyzed limb; secondly, providing simultaneously for thefreedom of movement of the foot about its natural anatomical axes sothat it can be positioned properly to perform a share of the bodysupporting function, and so that it can aid mobility during walking orarticulation of the limb; and thirdly, of providing for the applicationof external forces to replace the loss of muscle power or to overcome animbalancing of muscle forces about the various joints. The various formsof lower-leg brace-s usedprior to the present invention failed toprovide these necessary prerequisites for proper bracing because theydid not provide a means to compensate for the complex anatomicalstructure of the human leg, ankle and foot, the bones of whichconstitute the links of an internal mechanical system. For example, thelower-leg braces heretofore used provided articulation of the foot aboutonly one mechanical axis, and thus limited the foot to movement aboutonly one anatomical axis. One serious disadvantage with this arrangementwas that the wearer of the brace, being restricted by the brace to amovement having but a single degree of freedom, could not manipulate hisfoot to assume a proper position of alignment with the supporting bonesof the leg below the hip. Thus, in walking with such braces, the majorportion of the body weight often had to be supported by the arms insteadof the legs and this resulted in serious fatigue and discomfort. It alsoput greater stress on the bracing components which thus had to berelatively large to provide the necessary strength .and rigidity.

Another problem which arose as a result of the aforementioned lack ofarticulation about the natural joint axes, was that of compensating forabnormal muscle imbalance about certain joint axes which often occurs inleg paralysis cases. The braces heretofore used did not provide formovement about both of the major anatomical joints in the ankle and footand thus they did not provide .a means to supply forces to overcomeabnormal twisting of the foot due to such muscle defects. For example,

the lower-leg braces heretofore used had no means of serious(lllfiCllltlCS during walking since it prohibited the foot frompositioning itself with respect to the leg bones in order to support theweight of the body.

Still another problem with leg braces of the prior art "ice I was atendency for the brace members to shift their position during movementof the leg, thus causing chafing or constriction of the leg where thebrace cuff was attached to the leg. This problem primarily arose fromthe fact that the mechanical axis of the brace was not aligned with theanatomical axis of the equivalent joint. For example, during walking,the misalignment of the mechanical and anatomical ankle axis causedmovement of the brace cuff along the leg which resulted in chafing anddiscomfort to the brace wearer. In severe cases, additional accessorystraps were often required to maintain the brace in position.

The present invention solves the aforementioned problems and overcomesthe disadvantages of prior art lowerleg braces by providing a lower-legbrace having a novel combination of elements arranged toprovide two axesof articulation, thus forming an external mechanical bracing systemwhich affords the equivalent movement of the internal anatomical system.The brace components are arranged in a novel manner so that the twomechanical axes of movement become substantially aligned with the ankleaxis and subtalar axis of the foot when the brace is properly attachedto the wearer. Our invention also provides means for overcoming muscleimbalance, when necessary, by application of a tension means tocounteract abnormal rotation about a particular joint axis. Thus, theinvention provides for the maximum utilization of available musculatureconsistent with maximum mobility.

In summarizing the objects of the invention, one important object is toprovide a lower-leg brace which not only provides adequate support to adisabled or paralyzed limb but which is compatible with the kinematicsof the human anatomical foot structure and thus affords the full freedomof articulation of the foot about its natural anatomical axes.

Another object of the invention is to provide a brace that willcounteract abnormal unbalancing muscle forces in the partially paralyzedhuman foot to hold the foot in a desired position during walking.

Another object is to provide a brace that will provide a movement aroundmechanical axes coincident with the principal anatomical axes of thesubtalar and ankle joints when the brace is attached to the wearer.

Another object is to provide a lower-leg brace that eliminatesrestriction to movement about the natural anatomical axes of the footand is simple and light in con struction.

Another object of the invention is to provide a leg brace that isinexpensive to manufacture.

Another object is to provide a brace which is readily adaptable to thestatistical average foot configuration.

Another object of the invention is to provide a lowerleg brace thatenables articulation of the foot about both the ankle and subtalar axesby means of an external mechanical system that presents a minimum ofvisible mechanical linkage on the leg and foot of the wearer.

Other objects and advantages of the invention will be apparent from thefollowing detailed description taken in connection with the accompanyingdrawings in which:

FIG. 1 is a view in side elevation of the leg brace according to thepresent invention;

FIG. 2 is a view in perspective showing a skeletal structure of a humanfoot and indicating the major joints and axes of articulation of thefoot about the leg bones;

FIG. 3 is a view in rear elevation of the leg brace shown in FIG. 1;

FIG. 4 is a bottom view of the leg brace shown in FIG. 3 with the heelof the shoe removed to show the heel plate;

FIG. 5 is an enlarged fragmentary view showing the heel plate connectedto the bearing assembly on the yoke;

FIG. 6 is an enlarged fragmentary view in side elevation and in sectiontaken along the line 6-6 of FIG. 3 and showing the hinged connectionbetween the yoke and a side bar;

FIG. 7 is an enlarged fragmentary view in end elevation of the side barshown in FIG. 6.

The present invention provides a bracing device that not only furnishesfull support to a disabled leg but also solves the problem of providingan external mechanical system which affords normal articulation of thefoot about the natural joint axes. A leg brace 10 according to theprinciples of the present invention, is shown in FIG. 1, and comprises abase or heel plate 11 preferably fixed to the sole 12 of a shoe 13 wornon the disabled leg. A rearwardly extending portion of the heel plate 11forming a bearing support 14 extends beyond the rear end of the shoe 13.Attached to the bearing support 14 by means of a heel bearing assembly15 is a U-shaped yoke member '16. The bearing assembly 15 is adapted toprovide rotation of the yoke member 16 about a shaft 17 fixed to thebearing support 14. The axis of the shaft 17 is fixed at a predeterminedangle relative to the heel plate 11, so that it is substantially alignedwith the axis of the subtalar joint of the bracewearers foot whenpositioned within the shoe 13. The ends 18, 19 of the U-shaped yokemember 16 are hingedly attached to two supporting side bar members 20and 21 which extend upward from the yoke 16 generally parallel to theleg shank where they are connected to a cuff assembly 22 having a strap23 that enables the cuff to be tightened around the leg, preferably justbelow the knee.

In accordance with the principles of the invention, the lower-leg brace10 shown in FIGS. 1-3 provides for normal movement of the foot relativeto two major anatomical axes, and thus it comprises a novel solution tothe leg bracing problem that provides many important advantages overprior art braces. To illustrate some of the problems solved by theinvention, FIG. 2 shows the bones of a normal human foot and ankle whichform an ankle joint 25 at the juncture of the tibia 26 and the fibula 27with the surface of the talus 28. The axis of the ankle joint 25,indicated by line 29 extends through the ankle and is generallyhorizontal, thus providing the toe lifting movement of the foot. In thestrict anatomical sense the ankle joint has actually two axes, one beingcalled the dorsifiexion axis and the other, the plantar fiexion axis. Toavoid complication, these separate axes are not shown in FIG. 2 but line29 is shown as being their combined equivalent. The combined range ofmotions about two axes is approximately 50 to 62. When viewed from abovealong the tibia 26 when the foot is in the position of relaxed standing,the two axes are almost coincident, and when viewed from the front theseaxes form an angle of approximately 15 /2. With respect to the bracingproblem, we have discovered that a single external brace axis can servethe function of the two anatomical ankle axes if the mechanical braceaxis is located coincident to the average or combined equivalent of thetwo ankle axes represented by line 29 in FIG. 2. In locating the braceaxis, we have also discovered that for the most satisfactory braceoperation, the location of the mechanical ankle axis with respect toanatomical iankle axis must be more exact in the transverse plane thanin the vertical plane, where a certain degree of latitude may betolerated. This mechanical ankle axis is provided in our novel brace 10by a pair of hinge pins '30 which provide the connections between theyoke 16 and the side bars 20 and 21.

The second major joint of the human foot is the subtalar joint 32,which, as shown in FIG. 2, affords a sidewise tilting motion or alateral adjustment to the foot. The motion of the foot about the axis ofthe joint 32, designated by the line 33, is purely rotational, and therange of motion is limited to about 24 to 27. The axis 33 is skewed tothe ankle axis 29 and extends upward through the heel bone 36 at anangle to both the vertical and longitudinal coordinate axes 34 and 35 ofthe foot as shown in FIG. 2. The subtalar joint 32 is extremelyimportant to the leg bracing problem because it provides the means toposition the foot properly during walking and standing in so that it canmaintain its natural alignment with the upper leg and hip bones andtheir respective joints to thereby provide maximum support for the body.Without the capability of adjusting the foot position the properalignment cannot be maintained in the braced lower limbs, and as aconsequence the arms of the disabled person may be required to supportthe body weight during walking.

Describing now, the leg brace 10 in greater detail, FIG. 4 shows in planview the heel plate 11 which is preferably attached by some suitablemeans such as rivets 40 to the sole 12 of the shoe 13. The heel plate11, preferably formed from stainless steel, has essentially a T-shapeand is mounted near the rear end of the sole 12 where it is normallycovered by the heel 41 of the shoe 13. A transverse portion 42 of theT-shaped heel plate 11 extends across the sole 12 of the shoe 13 and hasan integral turned down lug member 43 at each end thereof which extendsover the edge of the sole 12. Extending rearwardly from the transverseportion 42 and along a line fixed at a predetermined angle to thecenterline of the shoe 12 is an integral portion 44 of the heel plate11. The portion 44 extends beyond the rear edge of the sole 12 and isbent upwardly at a fixed predetermined angle to form the bearing support14. The short shaft member 17 is fixed to the bearing support 14 asshown in FIG. 5, by a flange 45 at its upper end which is welded to thebearing support 14. The lower end of the shaft 17 is internally threadedto receive an end screw 46 which retains the bearing assembly 15 and theattached yoke 16 to the bearing support 14 of the heel plate 11. Theaxis of the shaft 17 extends forward at an angle A to the heel plate 11as shown in FIG. 1 and it also forms an angle B to the verticalcoordinate 34 as shown in FIG. 3. The shaft axis is thereby locatedsubstantially coincident with the anatomical axis 33 of the subtalarjoint 32 (FIG. 2) when the shoe 13 is placed on the foot. F or slightvariations in the actual location of the subtalar joint axis fordifferent persons, the position of the mechanical axis of the shaft 17can be adjusted by varying the length of the rearwardly extendingportion 44 of the heel plate 11 and its position on the shoe sole 12 andby varying the angle of the bearing support 14 relative to the plane ofthe heel plate 11 .The bearing assembly 15-, which may be of a standardcommercially available type, comprises a housing 47 that is preferablywelded to the yoke 16 and contains an outer ball bearing ring 48 fixedto the inner wall of the housing 47 and an inner ring 49 fixed to theshaft 17. Standard balls 56 positioned between the rings 48 and 49afford low friction movement of the bearing assembly 15 and the yoke 16,about the shaft 17. It is apparent that other suitable forms of bearingmeans for providing the rotational movement of the yoke 16 relative tothe heel plate 11 and the shoe 13 about an axis aligned with theanatomical axis of the subtalar joint of the foot on which the brace isworn, may be provided within the scope of the invention.

The yoke 16 attached to the bearing assembly 15 is generally U-shaped asseen in FIG. 3, having a curved center portion 51 to provide ampleclearance around the rear portion of the shoe 13 and upwardly extendingarms 52 and 53. The yoke arms 52 and 53 extend upward and forward at anangle to the horizontal and each has a predetermined length so that theyoke ends 18 and 19 can be connected by the hinge pins 30 to the sidebars 20 and 21 along an axis substantiallyialigned with the anatomicalankle axis 29 of the foot of the brace wearer. The hearing assembly islocated on the center curved portion 51 of the yoke 16 and it fitsaround the shaft 17 so that the yoke 16 thus is rotatable about thesubtalar axis 33 of the brace wearers foo-t when in the shoe 13.

The yoke 16 is preferably formed as an integral memher from somesuitable material such as steel rod stock. In forming the yoke 16, eachend 18- and 19 as seen in FIG. 16, is preferably flattened and thenbored to provide a hole 55 for attaching the yoke 16 to the side barsand 21. Adjacent each of the holes 55- is a projection 56 and anaccompanying notch 57 as shown in FIG. 6 which provides a seat or stopto limit the amount of movement of the yoke 16 with the side bars 20 and21.

The side bars 20 and 21 may be formed from a suitable strong but lightmetal such as aluminum and they are preferably flat and thin incross-section. The upper end 58 of each side bar 20, 21 is fixed to aleather lined cull assembly 22 of the well known type having a strap 23or some suitable means to hold the cuff 22 in position around the leg.At the lower end of each side bar 20, 21 is a portion 59 of increasedcross-sectional thickness and at the lowest extremity of each saidportion 59 is a birfurca-ted section 69 having two forked members 61 and62 as shown in FIG. 7. One member 61 may be provided with a round hole63 and the other member 62 may have a rectangular hole 64. Eachflattened end 18 and 19 of the yoke 16 is then adapted to fit, with easysliding clearance, between the forked members 61 and 62 of each side bar20 and 21, and a slot-headed pivot pin 39 is inserted through thebearing hole 63 and 64 on each side bar and the hole 55 on the yoke ends18 and 19 to provide the hinged connection between the side bars 20 and21 and the yoke 16. A nut 31 retains each hinge pin in the hole 64. v

In the lower enlarged portion 59 of each side bar 20, 21 is aninternally seated spring 65 that prov-ides a pivotal force on the yoke16 about the hinge pins 30 which, when applied through the heel plate 11serves to lift the toe of the shoe 13 automatically during walking. Ineach side bar 20, 21 as shown in FIG. 6, the spring 65 is located in atubular passage 66 which extends upward at an angle through the enlargedportion 59 of each side bar. The upper end of the passage 66 is threadedand closed by a plug 67 which seats the spring 65. By adjusting the plug67 in and out of the passage 66, a desired amount of spring force can bemaintained. The lower end of the spring 65- bears against the ballmember 68 which is retained at the lower end of the tubular passage 66.When the shoe 13 is in its normal level standing position, the notch 57and projection 56 on the ends '18, 19 of the yoke 16 form a seat for theball 68, thereby pressing against it and pushing it up into the passage66 to compress the springs 65. Thus, in walking, when the standingpressure is released, the springs 65, pressing againt the ball 68 andthus against the yoke 16, rotate the yoke 16 about the ankle axis hingepins 30 and lift up the toe of the shoe 13. This prevents toe draggingand greatly aids the walking process for those with disabled limbs.

As mentioned previously, a serious problem heretofore occurred in priorart braces when an imbalance of muscle tension caused an unnatural anduncontrollable tilting force on the foot about the subtalar axis. Thisoften resulted in improper foot alignment which prevented proper balanceand support. The present invention solves this problem by first,providing the combination of the heel plate 11, the bearing assembly 15,and the yoke .16 which together provide for rotation of the foot aboutthe anatomical subtalar axis. In addition, our invention provides aspring means 70, which may be attached at one end 71, as shown in FIG.2, to an outer turned down lug 43 on the heel plate 11, and at the otherend .to an attaching hole 72 near an end 18 or 19 of the yoke 16. Thespring '70 can be attached to either side of the shoe 13 to accommodatevarious muscle conditions in particular paralysis situation-s. Anysuitable spring tension means equivalent to the spring 70 can be used,and the spring 70 can be easily attachable or removable whenevernecessary.

In applying the brace 10 of the present invention to one requiringexternal leg support, the brace components may be formed and assembled,as described previously, so that the mechanical axes of movement of thebrace are coincident with the anatomical axes of the brace wearer whenthe brace is properly attached to the wearer. The exact location of theanatomical axes can be ascertained by one of several methods which arenot part of this invention. After assembly of the brace components theheel plate 11 is attached to the shoe 13 in the proper position so thatwhenever the brace is worn, the axis of the hinge pins 39 and the axisof the heel bearing shaft 17 are always automatically aligned with thenormal foot axes when the foot is placed in the shoe. A significantfeature of our invention is that its relative mechanical simplicitymakes it easy to make an adjustment in the brace components such asrelocation of the heel plate 11 on the shoe sole 12 or the angularorientation of the bearing support 14. Thus, the brace can be madecompatible an individual wearers leg and foot, and with the exactlocation of this ankle and subtalar joint axes, and a few basic sizescan easily accommodate a large percentage of wearers.

In cases where only limited bracing is required, a brace having a singleside bar 20 or 21 with its ankle joint assembly and half of the yoke 16,could be made within the scope of the invention. The side bar and yokeportion could be located on the side of the leg requiring the bracingstrength and a spring 70 could be attached in the aforementioned mannerto correct the muscle imbalance around the subtalar joint.

From the foregoing, it is apparent that the present invention provides asignificant advance in the vital field of limb bracing and prosthetics.During normal body movements the brace acts to provide constant supportand proper positioning of the feet relative to the legs. The springs 65acting around the ankle axis hinge pins 30 keep the toe lifted whenWeight is removed during walking, and the leveling springs 70 keep thefoot properly positioned so as to give support to the legs in the properalignment therewith. With all bodily movements, the foot, though wellsupported, can move with the normal degree of freedom about both majorfoot and ankle joints.

To those skilled in the art to which this invention relates, manychanges in construction and widely differing embodiments andapplications of the invention will suggest them-selves Without departingfrom the spirit and scope of the invention. The disclosures and thedescription herein are purely illustrative and are not intended to be inany sense limiting.

We claim:

1. A brace for supporting the lower leg and the foot of a human bysimultaneously providing free movement to the foot relative to the legabout its anatomical ankle and subtalar joints, said brace comprising: ashoe adapted to be worn on said foot; a mounting means fixed to saidshoe; a yoke mean movably connected to said mounting means about a firstpredetermined axis substantially aligned with the anatomical axis of thesubtalar joint of said foot Within said shoe; side bar means pivotallyattached to said yoke means along a second predetermined axissubstantially aligned with the anatomical axis of the ankle joint of thefoot within said shoe, said side bar means extending upward adjacentsaid leg; and means fixed to said side bar means for attaching saidbrace to the leg.

2. A brace for supporting the lower leg and the foot of a human whilesimultaneously providing free movement of the foot relative to the legabout its anatomical ankle and subtalar joints, said brace comprising: ashoe means adapted to be Worn on said foot; a heel plate fixed to saidshoe, said heel plate having an integral portion extending rearwardlythe heel end of said shoe and forming a bearing support; a cylindricalshaft connected to said bearing support and positioned thereon with theaxis of said shaft forming a predetermined angle with the plane of theheel plate and being substantially aligned with the anatomical axis ofthe subtalar joint of said foot in said shoe; a generally U-shaped yoke;21 first bearing means on said yoke attached to said shaft for providingrotation of said yoke about said shaft; end members on said yokeextending upward from said curved center portion; a second bearing meansconnected to said end members; side bar means pivotally attached to saidsecond bearing means, thereby providing for rotational movement of saidyoke relative to said bar means about the axis of said pin means, saidaxis of said second bearing means being substantially aligned with saidanatomical ankle axis said side bar means extending upward substantiallyparallel the side of said leg; and circular cuff means fixed to saidside bar means and adapted to fit around the leg for attaching saidbrace to the leg.

3. A brace for supporting the lower leg and the foot of a human whilesimultaneously providing free movement of the foot relative to the legabout its anatomical ankle and subtalar joints, said brace comprising: ashoe adapted to be worn on said foot; a heel plate fixed to said shoe,said heel plate having an integral portion extending rearwardly the heelend of said shoe and forming a bearing support; a cylindrical shaftconnected to said bearing support and positioned thereon with the axisof said shaft forming a predetermined angle with the plane of the heelplate and being substantially aligned with the anatomical axis of thesubtalar joint of said foot in said shoe; a generally U-shaped yoke; afirst bearing means on said yoke attached to said shaft for providingrotation of said yoke about said shaft; end members on said yokeextending upward from said curved center portion; a second bearing meansconnected to said yoke end members; side bar means pivotally attached tosaid second bearing means, thereby providing rotational movement of saidyoke relative to said bar means about the axis of said second bearingmeans, said axis of said' second bearing means being substantiallyaligned with said anatomical ankle axis, said side bar mean extendingupward substantially parallel to the side of said leg; spring-loadedmeans in said side bar means engaging said yoke ends to bias said yokein a predetermined direction relative to the side bar means to therebyautomatically lift the toe of said shoe during walking; and cuff meansfixed to the upper ends of said side bar means for attaching said braceto the leg.

4. A brace for supporting the lower leg and the foot of a humancomprising: a shoe adapted to be worn on said foot; a heel plate fixedto said shoe, said heel plate having a transverse portion extendingacross the width of said shoe and a longitudinal portion extendingbeyond the rear end thereof to form a bearing support, said bearingsupport being located in a predetermined position slightly to one sideof the longitudinal center line of said shoe; a yoke means rotatablyattached to said bearing support on said heel plate, the axis ofrotation of said yoke on said bearing mount being located in apredetermined position extending upward at an angle to said heel plateand through said shoe and thereby substantially aligned with thesubtalar axis of said foot when in place within said shoe; side barmeans pivotally attached to said yoke means on an axis substantiallyaligned with the ankle aXis of said foot when in place with said shoe,said side bar means extending upward along the side of said leg; andcuff means fixed to said side bar means for attaching said brace to saidleg.

5. The brace as described in claim 4 including a tension means attachedto one end of said transverse portion on said heel plate and to saidyoke means to provide a stabilizing force for overcoming muscleimbalance in said foot.

6. A brace for supporting the lower leg and the foot of a human whilesimultaneously providing free movement of the foot relative to the legabout its anatomical ankle and subtalar joints, said brace comprising: ashoe adapted to be Worn on said foot; a heel plate fixed to said shoe,said heel plate having an integral portion extending rearwardly the heelend of said shoe and forming a bearing support; a cylindrical shaftconnected to said bearing support and positioned thereon with the axisof said shaft forming a predetermined angle with the plane of the heelplate and being substantially aligned with the anatomical axis of thesubtalar joint of said foot in said shoe; a generally U-shaped yoke; afirst bearing means on said yoke attached to said shaft for providingrotation of said yoke about said shaft; end members on said yokeextending upward from said curved center portion; aligned second bearingmeans attached to said end members; side bar means connected to saidsecond bearing means and thus pivotally attached to said yoke endmembers, and providing for rotational movement of said yoke relative tosaid side bar means about the axis of said second bearing, the axis ofsaid second bearing means being substantially aligned 'with theanatomical ankle axis of the foot in said shoe means, said side barmeans extending upward substantially parallel the side of said leg;spring means connected from said heel plate to said yoke to provide abiasing force on said yoke about its axis to counteract an imbalancedmuscle force about said subtalar joint; and circular cuff means fixed tosaid side bar means and adapted to fit around the leg for attaching saidbrace to the leg.

7. A brace for supporting the lower leg and the foot of a human whilesimultaneously providing free movement of the foot relative to the legabout its anatomical ankle and subtalar joints, said brace comprising: ashoe adapted to be worn on said foot; a heel plate fixed to said shoe,said heel plate having an integral portion extending rearwardly the heelend of said shoe and forming a bearing support; a cylindrical shaftconnected to said bearing support and positioned thereon with the axisof said shaft forming a predetermined angle with the plane of the heelplate and being substantially aligned with the anatomical axis of thesubtalar joint of said foot in said shoe; a generally U-shaped yoke;bearing means on said yoke attached to said shaft for providing rotationof said yoke about said shaft; end members on said yoke extending upwardfrom said curved center portion; rotatable connection means attached tosaid yoke end members; side bar means pivotally attached to saidconnection means, thereby providing rotational movement of said yokerelative to said bar means about the axis of said connection means, theaxis of said connection means being substantially aligned with saidanatomical ankle axis, said side bar means extending upwardsubstantially parallel to the side of said leg; spring-loaded means insaid side bar means engaging said yoke ends to bias said yoke in apredetermined direction relative to the side bar means to therebyautomatically lift the toe of said shoe during walking; spring meansconnected from said heel plate to said yoke to provide a biasing forceon said yoke about its axis to counteract an imbalanced muscle forceabout said subtalar joint; and cutr' means fixed to the upper ends ofsaid side bar means for attaching said brace to the leg.

eferences on following page) 9 10 References Cited in the file of thispatent 2,959,168 Shook Nov. 8, 1960 2,973,757 Katthoefer Mar. 7, 1961UNITED STATES PATENTS OTHER REFERENCES Publication entitled New Horizonsin Brace Research, copyright-ed 1949, page 7 employed; on file in Div.55.

2,267,848 Taylor Dec. 30, 1941 2,516,872 Hauser :et a1. Aug. 1, 1950

3. A BRACE FOR SUPPORTING THE LOWER LEG AND THE FOOT OF A HUMAN WHILESIMULTANEOUSLY PROVIDING FREE MOVEMENT OF THE FOOT RELATIVE TO THE LEGABOUT ITS ANATOMICAL ANKLE AND SUBTALAR JOINTS, SAID BRACE COMPRISING: ASHOE ADAPTED TO BE WORN ON SAID FOOT; A HEEL PLATE FIXED TO SAID SHOE,SAID HEEL PLATE HAVING AN INTEGRAL PORTION EXTENDING REARWARDLY THE HEELEND OF SAID SHOE AND FORMING A BEARING SUPPORT; A CYLINDRICAL SHAFTCONNECTED TO SAID BEARING SUPPORT AND POSITIONED THEREON WITH THE AXISOF SAID SHAFT FORMING A PREDETERMINED ANGLE WITH THE PLANE OF THE HEELPLATE AND BEING SUBSTANTIALLY ALIGNED WITH THE ANATOMICAL AXIS OF THESUBTALAR JOINT OF SAID FOOT IN SAID SHOE; A GENERALLY U-SHAPED YOKE; AFIRST BEARING MEANS ON SAID YOKE ATTACHED TO SAID SHAFT FOR PROVIDINGROTATION OF SAID YOKE ABOUT SAID SHAFT; END MEMBERS ON SAID YOKEEXTENDING UPWARD FROM SAID CURVED CENTER PORTION; A SECOND BEARING MEANSCONNECTED TO SAID YOKE END MEMBERS; SIDE BAR MEANS PIVOTALLY ATTACHED TOSAID SECOND BEARING MEANS, THEREBY PROVIDING ROTATIONAL MOVEMENT OF SAIDYOKE RELATIVE TO SAID BAR MEANS ABOUT THE AXIS OF SAID SECOND BEARINGMEANS, SAID AXIS OF SAID SECOND BEARING MEANS BEING SUBSTANTIALLYALIGNED WITH SAID ANATOMICAL ANKLE AXIS, SAID SIDE BAR MEANS EXTENDINGUPWARD SUBSTANTIALLY PARALLEL TO THE SIDE OF SAID LEG; SPRING-LOADEDMEANS IN SAID SIDE BAR MEANS ENGAGING SAID YOKE ENDS TO BIAS SAID YOKEIN A PREDETERMINED DIRECTION RELATIVE TO THE SIDE BAR MEANS TO THEREBYAUTOMATICALLY LIFT THE TOE OF SAID SHOE DURING WALKING; AND CUFF MEANSFIXED TO THE UPPER ENDS OF SAID SIDE BAR MEANS FOR ATTACHING SAID BRACETO THE LEG.